Alkyl-substituted aromaticaliphatic carboxylic acid



Patented July 12, 1949 ALIPHATIC CARBOXYLIC ACID Orland M. Reiff, Ferdinand P. Otto, John 3.

Giammaria, and Edward A. Oberright, Woodbury, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application December 21, 1943,

Serial No. 515,152 r 9 Claims. (01. 260-413) This invention has to do with new chemical compounds or reaction products which may be generally designated as alkylated aromatic-aliphatic carboxylic acids or as alkyl-substituted aryl-aliphatic carboxylic acids. Although' the invention is broadly concerned w th chemical compounds or compositions coming within the abovedesignated general classification, it contemplates as a preferred group coming within such general classification those compounds or condensation products which are soluble or miscible with mineral oil.

Our invention is predicated upon the discovery that the oil-miscible compounds or condensation products contemplated herein when blended with a viscous mineral oil fraction, such as a hydrocarbon lubricating oil, will improve the oil in various respects. For example, we have found that the compounds or reaction products contemplated herein will improve the. viscosity and pour point of the oil.

The alkyl substituent on the aryl nucleus of the compounds or condensation productsgcontemplated herein act to impart oil-miscibility to the product and for the preferred general class of oil-miscible compounds this alkyl substituent should contain at least twenty carbon atoms. This especially-preferred sub-group of compounds having the so-called heavy alkyl groups of at least twenty carbon atoms (such as are derived, for example, from a Friedel-Crafts condensation with chlorinated parafiin wax) act to improve the characteristics of the oil noted above.

Since the oil-miscibility or solubility of these compounds or condensation products is controlled or governed by the heavy alkyl substituent, the

extent to which the aromatic nucleus is substituted vwith these heavy alkyl groups becomes an important factor in obtaining products having the desired properties. This degree of substitution in the aromatic nucleus will vary more or less depending upon the aliphatic hydrocarbon group which carries the carboxyl radical-that is, whether such group is a short or long chain hydrocarbon groupand will also vary depending upon whether or not the aromatic nucleus is monoor polycyclic and whether such nucleus carries other substituents. In general, it may be said, however, that the aromatic nucleus should have at least one of the nuclear hydrogen atoms substituted with analiphatic hydrocarbon boxyl group is derived from a low molecular weight acid such as acetic acid.

It is to be understood that the present invention is not concerned with mineral oil compositions, such compositions forming the subject matter of copending applications Serial No. 467,058, filed November 26, 1942, now abandoned, and Serial No. 314,794, filed January 20,'1940 (now Patent No. 2,316,889, issued April 20, 1943), to which reference is made forfurther details in the composition of these compounds or reaction products.

It is also to be understood that the present invention is not confined to the oil-miscible or oilsoluble compounds and that the use of the preferred oil-miscible compounds is not confined to the improvement of mineral oils, since this whole class of new materials. is possessed of valuable properties irrespective of oil-solubility. For example, the compounds or condensation products contemplated herein may be used as intermediates in the production of resins, resin-like materials, rubber substitutes, etc, Certain of the com-' pounds or compositions arepossessed of valuable pharmaceutical, insecticidal or similar properties. Numerous other uses and applications of the compounds or condensation products contemplated herein will be readily apparent to those skilled in the art from the following description of their compositions and typical methods for synthesizing them.

As aforesaid, the compounds or condensation products contemplated herein may be broadly designated as the alkyl-substituted aryl-aliphatic carboxylic acids. Thus, atypical compound or condensation product of the type contemplated herein may be represented by the general formula:

I. I nn-Qz-ooon wherein R represents-an aliphatic hydrocarbongroup; a: represents an integer from 1 to 5; z represents an organic radical, or, more specifically, an aliphatic or cycle-aliphatic hydrocarbon group, which is substituted for one of the nuclear hydrogen atoms in the aromatic nucleus. It will be observed that this compound is a condensation product of an anal-substituted aromatic compound and an aliphatic or cyclo-aliphatic carboxylic acid, wherein at least one nuclear hydrogen atom on the aromatic nucleus is substituted with an "alkyl-carboxy radical and wherein at least one other nuclear hydrogen atom is substituted with an aliphatic hydrocarbon radical.

It is to be understood, of course, that the aryl nucl'eus (disclosed in the formula above as a substituted phenyl group) may be either monoor polycyclic; also that it may carry other substituents, such as ester, keto, alkoxy, alkyl sulfide, aryl sulfide, halogen, amino, etc., as more fully disclosed in application Serial No. 314,794.

It is to be further understood that the term aliphatic carboxylic acids" used hereinafter is inclusive of cyclo-aliphatlc carboxylic acids, and may be derived from the corresponding organic acids of various molecular weights.

The general procedure for synthesizing the alkyl-substituted aryl-aliphatic carboxylic acids is to first form the alkyl-substituted aromatic compound and then substitute one of the nuclear hydrogen atoms of the aromatic nucleus with an aliphatic carboxylic acid group such that a carbon atom of the, aliphatic radical of the aliphatic ,carboxylic acid group is directly. attached to a carbon atom of said aromatic nucleus.

Specific procedures which maybe followed in effecting the condensation between the alkylgsubstituted aromatic compoundrand the aliphatic acid are as follows:

(a) Condensation of an alkylated aromatic or an hydroxy-aromatic compound with an unsaturated aliphatic acid such as oleic acid, using a so-called kationoid catalyst such as sulfuric acid, zinc chloride, aluminum chloride, etc., to effect the addition of the unsaturated acid to the aryl nucleus.

-preference is given to mixed high molecular be carried out in various ways. A preferred procedure is to subject an aromatic compound, or a hydroxyaromatic compound which contains an hydroxyl group on the aromatic nucleus, to a Friedel-Crafts condensation reaction with a halogenated aliphatic hydrocarbon, which for obtaining the preferred multi-functional addition agents should be an aliphatic hydrocarbon containing at least twenty carbon atoms or a mixture of aliphatic compounds predominantly comprised of compounds having at least twenty carbon atoms. This alkylation may also be carried out with unsaturated hydrocarbons or aliphatic alcohols, using H2804 or anhydrous aluminum chloride as a catalyst. In alkylating phenols with high molecular weight alcohols, however, it is preferred to convert the alcohol to the corresponding halide (or polyhalide) and then condense the alkyl halide with the hydroxyaromatic compound by the Friedel-Crafts reaction. For obtaining the preferred multi-functional addition agent with unsaturated hydrocarbons or aliphatic alcohols they should be high molecular weight compounds containing at least twenty carbon atoms, such, as, for example, eicosylene, cerotene, melene, polymerized isobutylene, etc., and myricyl alcohol, ceryl alcohol, etc.

The Friedel-Crafts synthesis is preferred for obtaining the alkylated hydroxyaromatic compound, and as a source of the 'alkyl substituent weight hydrocarbons typified by those which characterize the heavier products of petroleum, such as heavypetroleum oils of the lubricant type, petrolatum and crystalline petroleum wax or other compounds which will result in relatively long chain aliphatic substituents. Special pref- (b) Condensation of an alkylated aromatic or hydroxyaromatic hydrocarbon with an halogenated aliphatic or cycloaliphatic acid, such as chloracetic, chlorstearic and chlornaphthenic acids, by means of the Friedel-Crafts reaction using anhydrous aluminum chloride as the preferred catalyst.

(c) In the case of acids of the type contemplated herein which contain a hydroxyl substituent in the aromatic nucleus, such acids may be prepared by a re-arrangement of the corresponding alkylated aryl ether aliphatic acids in the presence of a kationoid catalyst such as HCl gas.

(11) Hydroxyaryl-aliphatic acids can be converted to the corresponding ether aryi-aliphatic acids by methylating the hydroxyl group by reaction with aikyiating agents like dimethyl sulfate or alkyl halides or by reaction with arylating agents such as aryl halides.

In the event a compound is desired in which th aromatic nucleus contains as a substituent alkoxy, ester, nitro, or amino groups, it is necessary to introduce such groups into the compound after the condensation with the aliphatic acid has been completed.

Methods for the introduction of such substituents will be apparent from methods described in my aforesaid copending application Serial No. 314,794.

The alkylation of the aromatic compound may erence is given to petroleum wax (paraffin wax) of melting point not substantially less than about R, which is predominantly comprised of allphatic hydrocarbons having a molecular weight of at least 350 and containing at least twenty carbon atoms.

Examples of the aromatic compounds which may be used as starting materials for the alkylation or wax-condensation reaction for obtaining either a product in which the aromatic nucleus is otherwise unsubstituted or a product in which the aromatic nucleus carries a hydroxyl group are as follows: benzene, naphthalene and anthracene (either substituted or unsubstituted) phenol, chiorphenol, resorclnoi, hydroquinone, catechol, cresol, hydroxydiphenyl, benzylphenol, alphaand beta-naphthol and beta-methylnaphthol, anthranol, phenyl-methylnaphthol, etc.; and aryl ethers such as diphenyl ether and naphthyl ether, or mixed alkyl-aryl or aralkyl-aryl ethers such as anisole, naphthylmethyl ether and benzylphenyl ether. Preference in general, as has been previously indicated, is to the monoand polycyclic aromatics (preferably naphthalene) and to the mono-hydroxyphenols otherwise unsubstituted, particular preference being given to phenol and alphaand beta-naphthol.

As has been previously indicated, the alkylcarboxyl substituent may be derived from any aliphatic or cyclo-aliphatic monoor polybasic carboxylic acid, illustrative sources of which are acetic, butyric, valeric, heptylic, nonylic, palmitic, and stearic acids, which typify saturated acids, and must be used as the corresponding halogenacid in which substitution takes place predominantly at the alpha carbon atoms of the aliphatic acid group. Other aliphatic acid substituents may be obtained by using unsaturated acids such v as oleic acid, CnHQMiOI in which case substitution on the nucleus takes place at the double bond in the unsaturated acid. Halogenated cyclo-aliphatic acids such as chlornaphthenic acid may be used to obtain compounds in whichthe alkyiated aromatic group carries a cycloaliphatic substituent.

As aforesaid, the preferred products contemplated herein are those having multi-functional properties wherein the alkyl substituent in the aryl nucleus contains at least twenty carbon atoms. In this preferred class of compounds, special preference is given to the condensation products derived rrom alkyl-substituted hydroxyaromatic compounds in which the alkyl substituent is derived from petroleum wax. The details in a typical procedure for synthesizing' these so-called wax substituted hydroxyaromatic compounds are described in prior application Serial No. 206,683, now Patent 2,197,833. Briefly, this procedure involves reacting a chlorinated wax such as chlorinated paraflin wax with a phenol in the presence of a Friedel-Crafts catalyst at elevated temperature. The chlorinated wax should have a chlorine content of from per cent to about per cent, and the obtained from such a reaction mixture may be designated as wax-phenol (3-16). Parenthetical expressions of the type (A-B) will be used hereinafter in connection with the wax-substituted derivatives to designate (a) the number of atomic proportions of chlorine in the chlorinated wax reacted with one mol ofaromatic compound and (b) the chlorine content of the chlorinated wax. I In the above example A=3 and B=16. The same designation will also apply to the waxsubstituted aryl aliphatic carboxylic acids which constitute the ultimate product derived from the corresponding wax-substituted aromatic compound.

The details in the procedure which may be followed in synthesizing alkylated aromatic-aliphatic carboxylic acids of the type contemplated herein will be best understood from the following examples of specific procedures used in synthesizing typical complex acids. It is to be understood in this connection that these examples are for illustration only and that the procedure may be varied by varying the specific reactants and the proportions thereof ExAmPLr: I

Preparation of wax-substituted hydroxyphenyl stearic carboxylic acids (a) Reactionmixture:

' Mol Wax-Phenol (3-16) 1 Oleic Acid 1 A10]: 1

('b) Condensation of Unsaturated aliphaticcarboxylic acids with wax-substituted hydroxyaromatic compounds chloride is necessary to control the evolution of HCl gas. The reaction temperature is then raised to. about 250! E, the mixture being held at out preferably in the presence of a diluent such as benzol or Stoddard Solvent, thereafter distilling the solvent, whereby any entrained water is removed. This is followed by introduction of superheated steam at a temperature of about 390 F. The operation of steam-treating is facilitated by vigorous stirring, the steam bein passed through the mixture until the distillate shows a negligible neutralization number, indicating that all unreacted aliphatic acid in the product has been removed. When the steam treatment is finished, which may require about 10 hours, steam vapors are removed from the condensation product by blowing with a nonoxidizing gas such as nitrogen, thereby yielding an anhydrous product. The product of this reaction is wax-substituted (3-16) hydroxyphenol stearic acid and distinguishes from the corresponding stearic acid obtained from chlorstearic acid in that the substitution of the stearic acid group has been effected at an intermediate point in the chain.

Following the foregoing procedure and using a poly-carboxylic acid such as maleic acid a dicarboxylic product is obtained, in this particular case the product being a Wax-substituted hydroxyaryl succinic acid.

Wax-hydroxyphenyl stearic and wax-hydroxyphenyl capric acid have been prepared following the foregoing procedure by employing instead of the unsaturated acid in the oleic mixture one mol of a chlor-acid in the two cases mentioned, the acids being chlor-stearic acid and chlor-capric acid, respectively.

- EXAMPLE II Preparation ofwaz-substituted naphthyl ali- I phatz'c carboxylic acids trated by the following procedure used inpreparing such acids wherein the aromatic nucleus is a naphthyl group.

(a) Reaction mixture: Y Mol Wax-Naphthalene (3-19) 1 Oleic Acid l A1013 1 (b) Condensation of wax-substituted naphthalene with aliphatic carboxylic acids The wax naphthalene (3- 9) of the type obtained according to the procedure outlined in the aforesaid patent, 2,197,833, and the oleic acid are mixed together and heated to a temperature of about F. One-moi of aluminum chloride is then added to the reaction mixture with stirring to avoid too rapid evolution of HCl, and the temperature is raised to about 250 F., Where it is held during a one-hour period to complete the reaction. The reaction mixture is purified in the same manner employed for the purification oi 7 the wax-hydroxyaromatic stearic acid described in Example I. Polybaslc alkylated aromatic-allphatic acids can be obtained by using unsaturated polybasic acids such as maleic acid, for example, in the foregoing procedure, which gives an aikylated aryl succinic acid.

Wax-naphthalene alpha-stearic acid can be obtained by using the foregoing procedure and a reaction mixture consisting of one mol of waxsubstituted naphthalene, one moi of chlor-stearic acid, and two mois of aluminum chloride.

EXAMPLE III Preparation war-substituted ether aryl aliphatic carboazylic acid Compounds of the type in which an additional substituent group in the alkyl-substituted aromatic-aliphatic carboxylic acids contemplated herein is an alkoxy or an aroxy group can be prepared by condensation of alkylated (such as wax-substituted) aryl ethers with unsaturated aliphatic acids such as oleic acid, using so-called kationoid catalysts, to obtain the final complex acid. Haiogenated aliphatic acids or halogenated cycle-aliphatic acids such as chlor-stearic and chlor-naphthenic acids can be used in place of unsaturated aliphatic acids, using A1013 as catalyst for the reaction.

These acids Can also be prepared from hydroxy-aryl aliphatic acids of the type derived by the procedure of Example I by alkylatin the hydroxyl group. The alkali salt of the hydroxyaryl aliphatic acid is treated with an alkyl sulfate such as dimethyl sulfate or with alkyl or aryl halides to form the ether derivatives.

These general procedures are more ,fully illustrated in the following examples:

(b) Condensation of wax-substituted diphenyl ether with aliphatic carboxylic acids One mol of a Wax-diphenyl ether (346) prepared as outlined in Patent 2,197,833, was mixed with one mol'of oleic acid and a mol of AlCla was gradually added to the mixture with stirring at a temperature of about 150 F. The reaction was carried to completion by raising the temperature of the mixture to about 250 -F. and holding at this point during a one-hour period.

Upon cooling to about 150 F. the reaction mixture was treated with water and kept acidic with aqueous HCl to remove all traces of aluminum, thereafter water-washing the mixture until the washings become neutral to litmus. The operation of water-washing can be facilitated by use of a diluent such as Stoddard Solvent. The finished product is obtained by removal of the diluent by distillation, whereby the removal of entrained water is also eifected.

When high molecular weight aliphatic acids such as oleic acid or high molecular weight cycyo-aliphatic acids such as naphthenic acid are used in the condensation reaction, the use of superheated steam is required for removal of unreacted aliphatic acid. This treatment is carried out by running steam into the mixture at a temperature of about 200 C. after removal of the AlCla by water-washing. The steam-treating is carried out until the distillate shows negligible acidity.

The condensation of halogenated aliphatic acids with diaryl ethers is carried out by the same procedure outlined above for the unsaturated acids.

EXAMPLE IV Preparation of ether aryl aliphatic carboxylic acids from hydrozyaryl aliphatic carborylic acids ((1) Reaction mixture: Mols Wax-hydroxy phenyi stearic acid (3-16)--- 1 Metallic sodium 2 Dimethyl sulfate 1 (b) Procedure:

One mol of wax-hydroxyphenyl stearic acid (3-16) was dissolved in butyl alcohol and two atomic proportions of metallic sodium were added. The reaction mixture was heated at approximately F. for hour to form the di-sodium salt of wax-hydroxyphenyl stearic acid. The reaction mixture was cooled to room temperature and one mol of dimethyl sulfate added. After stirring for one hour the mixture was heated at approximately F. for two hours to complete the reaction.

Any ester formed in the reaction was saponified by adding aqueous NaOH and refluxing for several hours. The mixture was then acidified with aqueous I-ICl to give free wax-substituted ether aryl aliphatic acid, which was then washed free of mineral acid. (The addition of Stoddard Solvent facilitates the water-washing.) The finished product was obtained by removal of any diluent (including entrained water) by distillation. The product of the procedure was waxmethoxyphenyl stearic acid (3-16).

EXAMPLE V Preparation of wax-substituted ester aryl aliphatic carbozcylic acids Compounds of this type are those in which the aryl nucleus carries an organic ester group in addition to the characterizing heavy alkyl group and the characterizing aliphatic carboxylic acid group. They may be prepared from waxsubstituted hydroxyaromatic aliphatic acids of the type described in Example I by reaction with a monoor dibasic acid chloride, using AlCl: as a catalyst. This reaction yields what we may term the ester (corresponding to the acid chloride) of the wax-hydroxyaromatic-aliphatic carboxylic acid, such as, for example, the phthalyl ester of wax-hydroxyphenyl stearic acid (3-16).

It will be understood that when a mixture of aliphatic hydrocarbon compounds, such as petroleum wax, for example, is used as the source of the alkyl substituents, the resulting composition will be an intimate mixture of compounds or alkyl-substituted aryl aliphatic carboxylic'acids, which compounds diifer from each other with respect to the nature of the alkyl substitutent. In other words, where the alkylation of the aryl nucleus has been effected with a mixture of allphatic hydrocarbons, the resulting product will likewise be a mixture of compounds diflering with respect to the alkyl substituent but having in common the same aliphatic carboxylic acid group and the same characterizing arylnucleus dis phatic carboxylic acids which we have prepared and tested to demonstrate their value as addition agents for viscous mineral oils.

Table One I Wax-hydroxyphenyl stearic acid (3-14) Wax-cresol stearic acid (2-16) Wax-naphthol stearic acid (3-14) Wax-amyl beta-naphthol stearic acid (3-18) Phthalyl ester of wax-hydroxyphenyl stearic acid (3-16) It is to be understood that although we have described certain preferred procedure for synthesizing the products contemplated by this invention and have listed a number of illustrative compounds or condensation products which are typical thereof, the invention is not limited to the particular procedures or products but includes within its scope such changes and modifications as fairly come within the spirit of the appended claims.

We claim:

1. As a new composition of matter, an akylsubstituted carbocyclic aromatic-aliphatic carboxylic acid in which a carbon atom of the aliphatic radical of the aliphatic carboxylic acid group is directly attached to a carbon atom of the carbocyclic aromatic nucleus, and in which the alkyl substituent is attached to the ,carbocyclic aromatic nucleus and contains at least twenty carbon atoms.

2. As a new composition of matter, an alkylsubstituted carbocyclic aromatic-aliphatic carboxylic acid in which a carbon atom of the aliphatic radical of the aliphatic carboxylic acid group is directly attached to a carbon atom of the carbocyclic aromatic nucleus, and in which the'alkyl substituent contains at least twenty carbon atoms and is attached to the carbocyclic aromatic nucleus and said carbocyclic aromatic nucleus contains at least one ether substituent.

3. As a new composition of matter, an alkylsubstituted carbocyclic aromatic-aliphatic carbox'ylic acid in which a carbon atom of the allphatic radical of the aliphatic carboxylic acid group is directly attached to a carbon atom of the carbocyclicaromatic nucleus, and in which the alkyl substituent is attached to the carbocyclic aromatic nucleus and said carbocyclic aromatic nucleus contains at least one ester substituent.

4. As a new composition of matter, an alkylsubstituted phenol stearic acid, the said alkyl substituent having at least twenty carbon atoms.

5. As a new composition of matter, an alkylsubstituted methoxy-phenyl stearic acid, the said alkyl substituent having at least twenty carbon atoms.

6. As a new composition of matter, the phthalyl ester of an alkyl-substituted hydroxyphenyl stearic acid, the said alkyl substituent having at least twenty carbon atoms.

7. As a new composition, an intimate mixture of alkyl-substituted carbocyclic aromatic-aliphatic carboxylic acids in which a carbon atom of the aliphatic radical of the aliphatic carboxylic acid group is directly attached to a carbon atom of the carbocyclic aromatic nucleus, and in which the alkyl substituents have at least twenty carbon atoms, the compounds diifering with each other in the alkyl substituent.

8. As a new composition of matter, an alkylsubstituted nuclear hydroxylated carbocyclic aromatic-aliphatic carboxylic acid in which a carbon atom of the aliphatic carboxylic acid group is directly attached to a carbon atom of the carbocyclic aromatic nucleus and in which the alkyl substituent is attached to the carbocyclic aromatic nucleus.

9. As a new composition of matter, an alkylsubstituted phenyl stearic acid, said alkyl substituent having at least twenty carbon atoms.

' ORLAND M. REIFF.

FERDINAND P. OTTO. JOHN J. GIAMMARIA. EDWARD A. OBERRIGHT.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 2,197,833 Reifli Apr. 23, 1940 2,198,274 Reiif Apr. 23, 1940 2,239,533 Mikeska Apr. 22, 1941 2,316,889 Reiif Apr. 20, 1943 OTHER REFERENCES Gilman, Organic'Chemistry, edition 2, volume 1, pages 117, 118, 119, and 127, Wiley, N. Y., 1943. a 

